Voltammetric Determination of Meloxicam in Pharmaceutical Formulation and Human Serum at Glassy Carbon Electrode Modified by Cysteic Acid Formed by Electrochemical Oxidation of L-cysteine

Metal-Based Nanomaterials for the Sensing of NSAIDS

Cadmium sulfide and zinc oxide nanoparticles were prepared, characterized and used as electrode modifiers for the sensing of two non-steroidal anti-inflammatory drugs (NSAIDs): naproxen and mobic. The structural and morphological characterization of the synthesized nanoparticles was carried out by XRD, UV-Vis spectroscopy, FTIR and scanning electron microscopy. The electrode's enhanced surface area facilitated the signal amplification of the selected NSAIDs. The CdS-modified glassy carbon electrode (GCE) enhanced the electro-oxidation signals of naproxen to four times that of the bare GCE, while the ZnO-modified GCE led to a two-fold enhancement in the electro-oxidation signals of mobic. The oxidation of both NSAIDs occurred in a pH-dependent manner, suggesting the involvement of protons in their electron transfer reactions. The experimental conditions for the sensing of naproxen and mobic were optimized and, under optimized conditions, the modified electrode surface demonstrated the qualities of sensitivity and selectivity, and a fast responsiveness to the target NSAIDs.

Meloxicam

Meloxicam, an oxicam derivative: 4-Hydroxy-2-methyl-N-(5-methyl-2-thiazolyl)-2H-1,2- benzothiazine-3-carboxamide 1,1-dioxide, is a nonsteroidal anti-inflammatory drug (NSAID). It is a selective inhibitor of cyclooxygenase-2 (COX-2). It is used in the management of rheumatoid arthritis, acute exacerbations of osteoarthritis, ankylosing spondylitis and juvenile idiopathic arthritis. It is given in a single oral dose of 7.5mg, increased if necessary to a maximum of 15mg daily (7.5mg in the elderly). It may also be given by rectal suppository in doses similar to those used orally. The reported side effects of meloxicam are similar to those of nonsteroidal anti-inflammatory drugs (NSAIDs), such as abdominal pain, anemia, and edema. There is also an increased risk of serious gastrointestinal (GI) adverse events, including ulceration and bleeding. This profile is prepared to discuss and explain physical characteristics, Proprietary and nonproprietary names of meloxicam. It also includes methods of preparation, thermal and spectral behavior, methods of analysis, pharmacokinetics, metabolism, excretion and pharmacology.

Electro-Oxidation Mechanism of Meloxicam and Electrochemical Sensing Platform Based on Graphene Nanoparticles for its Sensing Pharmaceutical Sample

Background:

Electrochemical oxidation mechanism and electrochemical determination of meloxicam (M), an anti-artrithtis agent, were investigated by cyclic voltammetry and square wave adsorptive stripping voltammetry, respectively. </P><P> Objective: In this study, we aimed to investigate the electrochemical redox mechanism and develop a nano-sensor for sensitive, fast and selective analysis of meloxicam.

Methods:

In this study, the three-electrode system was used for all voltammetric measurements. Firstly, the graphene content of GR/CPE sensor was changed in the range of 1.67% to 6.68%. Then, the surface characterization of modified electrode was carried out by using Electrochemical Empedance Spectroscopy and Surface Electron Microscopy methods. Some analytical parameters, such as pH, accumulation potential and accumulation time were optimized and by using optimum parameters, calibration study was established.

Results:

The GR/CPE with a graphene content of 3.33 % was found to have the best voltammetric signal with a linear working range of 0.1–10 µM. The sensitivity of the quantitative voltammetric method towards M is fairly good with an LOQ of 0.0088 μmol/L and LOD of 0.0026 µmol/L.

Conclusion:

The optimum pH, accumulation time and accumulation potential were found to be 2.0, 150s and 0.0 V, respectively. The height of the voltammetric signal obtained with the GR/CPE electrode was stable with a 4.0 % deviation for a period of not shorter than 1 months.

Ultrasound-accelerated synthesis of gold nanoparticles modified choline chloride functionalized graphene oxide as a novel sensitive bioelectrochemical sensor: Optimized meloxicam detection using CCD-RSM design and application for human plasma sample

In this research, gold nanoparticles modified choline chloride functionalized graphene oxide (AuNPs-ChCl-GO) was synthesized through the assistance of ultrasound and fabricated as a novel bioelectrochemical sensor and utilized for the sensitive detection of meloxicam (MEL). The morphological and structural features of the AuNPs-ChCl-GO were characterized using different techniques including FTIR, TEM, FE-SEM, EDX, and XRD. The modified electrode showed a remarkable improvement in the anodic oxidation activity of MEL due to the enhancement in the current response compared to the bare carbon paste electrode (CPE). The biosensor composition and measurement conditions were optimized using an experimental design. The differential pulse voltammetry (DPVs) exhibited expanded linear dynamic in the range of 9.0 × 10^-9 to 8.5 × 10^-7 M for MEL in Britton-Robinson buffer at pH = 4.0 with a detection limit of 1.008 × 10^-9 M. The practical utility of the modified electrode was demonstrated by the accurate detection of MEL in human plasma sample.

Quantitation of meloxicam in the plasma of koalas (Phascolarctos cinereus) by improved high performance liquid chromatography

An improved method to determine meloxicam (MEL) concentrations in koala plasma using reversed phase high performance liquid chromatography equipped with a photo diode array detector was developed and validated. A plasma sample clean-up step was carried out with hydrophilic- lipophilic copolymer solid phase extraction cartridges. MEL was separated from an endogenous interference using an isocratic mobile phase [acetonitrile and 50 mM potassium phosphate buffer (pH 2.15), 45 : 55 (v : v)] on a Nova-Pak C18 4-µm (300 × 3.9 mm) column. Retention times for MEL and piroxicam were 8.03 and 5.56 min, respectively. Peak area ratios of MEL to the internal standard (IS) were used for regression analysis of the calibration curve, which was linear from 10 to 1,000 ng/mL (r(2) > 0.9998). Average absolute recovery rates were 91% and 96% for MEL and the IS, respectively. This method had sufficient sensitivity (lower quantitation limit of 10 ng/mL), precision, accuracy, and selectivity for routine analysis of MEL in koala plasma using 250-µL sample volumes. Our technique clearly resolved the MEL peak from the complex koala plasma matrix and accurately measured MEL concentrations in small plasma volumes.